Noibat is a pale purple bat-like Pokémon. It has yellow eyes, a black triangular marking on the inner corner of each eye, three tufts of spiked fur on each cheek, two dark purple teardrop-shaped spots on the front of its face forming the shape of a nose-leaf, a black lower jaw, and two spiked tufts of fur on its upper lip. Its large, teardrop-shaped ears resemble loudspeakers; they are dark purple on the outside with alternating rings of pale and dark purple fading to black on the inside. Fluffy black fur covers its chest and hips. On the middle joint of its wings are small black hands with two fingers, and it has two long toes on each foot.
Noibat can be found in pitch black caves. They rest in the caves during the day and only leave during the night. From its large ears, it is capable of emitting any kind of wavelength of sound, including ultrasonic waves of up to 200,000 Hertz. It uses these waves to stun large creatures, communicate with other Noibat, and immobilize prey. It also uses ultrasonic waves to perceive its surroundings, allowing it to fly in the dark. It is very fond of fruits, and uses its sonar to detect its ripeness. It tends to mistake Applin for its food.
Noibat has the lowest base stat total of all Dragon-type Pokémon.
In addition, Noibat has the lowest base Attack stat of all Dragon-type Pokémon.
Noibat's German name, eF-eM, is the only Pokémon name that uses the Latin alphabet and does not start with a capital letter.
Originally, Noibat's Pokédex entry on the official Pokémon website was incorrect, showing it as a pure Flying-type Pokémon. It has since been rectified.
Noibat can be seen as a parallel to Zubat, as they are both Flying-type Pokémon based on bats and can have Infiltrator as a possible Ability. They also share the same base stats, with their Attack and Special Attack switched around.
Noibat may be based on a bat, and the design of its ears may be based on speakers.